Field of the Invention
The present invention relates to an image stabilizer that is installed in an optical apparatus such as a lens apparatus or an image pickup apparatus like a digital camera or a digital video camera.
Description of the Related Art
An image stabilizer installed in a digital camera or the like is configured to move a movable member that holds a correcting lens or an image pickup element as an image-blur correcting optical system in two directions (yaw and pitch directions) orthogonal to an optical axis. In this configuration, the influence caused by a hand shake generated in an image shooting can be absorbed. Japanese Patent Laid-open No. H09-105973 discloses a configuration in which a movable member that holds a correcting lens is rotationally moved in two direction on a spherical surface around a predetermined point as a spherical center on the optical axis of the correcting lens.
Lens units that constitute an optical apparatus move in the optical axis direction when zooming or focusing is performed. When the correcting lens is rotationally moved, it is preferred that a radius of curvature of the rotational movement of the correcting lens be changed depending on a position of the lens units in the optical axis direction in order to optimize the optical performance.
In the configuration disclosed in Japanese Patent Laid-open No. H09-105973, however, the position of the spherical center of the rotational movement of the correcting lens is fixed. In other words, the radius of curvature of the spherical surface where the correcting lens rotationally moves is constant. Accordingly, in the configuration disclosed in Japanese Patent Laid-open No. H09-105973, it is difficult to optimize the optical performance when the correcting lens is rotationally moved depending on the position of the lens units in the optical axis direction.